Pollutants such as nitrogen oxides, sulfur oxides, carbon monoxide, and hydrocarbons contained in exhaust gas are a great threat to the human environment. Countries are also strengthening regulations on harmful exhaust gas or accelerating the development of technologies for reducing harmful emissions.
Automobiles with the largest emissions have a direct impact on the on-the-ground environment in which humans live. As a result, regulatory demands have been high and treatment technologies have been advancing early. However, regulation of exhaust gas of ships has been relatively recently started and International Maritime Organization (IMO) and advanced countries are actively preparing countermeasures.
In the field of NOx reduction among green ship exhaust gas treatment technologies to respond to environmental regulations related to shipbuilding and shipping industry of IMO, a selective catalytic reduction (SCR) system with proven performance, safety and economic efficiency is getting popular.
The SCR system includes a reactor equipped with a honeycomb structure catalyst support. The catalyst support induces the exhaust gas mixed with NOx and ammonia (NH3) to generate nitrogen and water through a reduction reaction. As a material of the catalyst support, a ceramic extruded material which is easy to be mass-produced at low cost has been devised, but the use of a metal support which can be manufactured with a thin thickness and has excellent mechanical properties is also increasing.
Korean Patent Application Publication No. 10-2012-0117426 discloses a structure in which a large-capacity catalyst support is manufactured in the form of a unit catalyst support block and then assembled, but has a complicated structure having a lot of fastening points in which an assembly member is an element center for being engaged between adjacent unit catalyst support blocks.
In addition, the unit catalyst support block includes a support for accommodating and inserting cell forming bodies as a polygonal structure in which each of the cell forming bodies having a plurality of hollow cells corresponds to the shape of the cell forming bodies by a wave plate/flat plate assembly fabricated from a wave plate and a flat plate made of a thin metal plate coated with a catalyst on the surface thereof.
Furthermore, conventional metal supports implemented by using the wave plate/flat plate assembly fabricated from a wave plate and a flat plate made of a thin metal plate coated with a catalyst on the surface thereof use an integrated wave plate/flat plate assembly fabricated by using a joining method such as brazing, welding, soldering, and diffusion bonding, thereby causing low productivity and making it difficult to secure price competitiveness.
In addition, when the wave plates and the flat plates are alternately stacked, the vertexes of the wave plates do not coincide with each other, so that the wave plates and the flat plates may be deformed due to external vibration, shock, or temperature change.